I have Ghostwalk but I always thought to use it in its own world, even if it's not very developed beyond the surrounding region.
However a few days ago I saw it was listed in the Forgotten Realms wikia among 3ed FR products... Probably an error, there is nothing explicitly tying it to the FR, the assumptions about life after death are quite different...
Page 134 of Ghostwalk explicitly says it is intended as a stand-alone setting. It however suggest to place it in a remote area of your campaign world to explain while rules about life and death are different around the city of Manifest.
In the Forgotten Realms the book suggest to place Manifest in Lantan, Moonshae or Tashalar. The latter could be the best choice, having yuan-ti nearby.
It also suggest to unify Ghostwalk's deities with some FR ones, or even place Ghostwalk in an undeveloped part of Maztica and keep the same deities (Ghostwalk's common culture however seems a bit too european for Maztica...)
The book also has suggestions for Greyhawk: replace the Yeomanry and the Hold of the Sea Princes, or the Amedio Jungle, or the Lendore Isles or the eastern part of the old Great Kingdom. It also suggest to unify Ghostwalk deities with Greyhawk ones.
In Mystara, IMO the most appropriate location could be north eastern Davania.
If a DM wants to use Manifest, I guess he/she could also decide the city has multiple manifestations in different worlds

The Lendore Isles make a lot of sense for Manifest, since in Ghostwalk elven souls become one with the trees in the wood outside the city, while in From the Ashes the Lendore Isles are where elves retreat after they weary of the world. It also explains, and helps justify, why the elves would eventually decide that Lendore Island should be restricted to elves only and drive other races from the island; they're protecting the wood that contains the souls of their race.

Sturm wrote:Page 134 of Ghostwalk explicitly says it is intended as a stand-alone setting. It however suggest to place it in a remote area of your campaign world to explain while rules about life and death are different around the city of Manifest.
In the Forgotten Realms the book suggest to place Manifest in Lantan, Moonshae or Tashalar. The latter could be the best choice, having yuan-ti nearby.

But using materials from Ghostwalk piecemeal can be done "as is". Because the more you look at Forgotten Realms, the more does this place teem with non-corporeals.
Such as watchghosts, spectral harpists and silveraith (sigh), in addition to more "common" ghosts (including dragon and beholder variants) and banshees... Not only undead non-corporeals, at that - there are crimson death, firetails and whatnot. See also Realms by Night saved here.

Havard wrote:What settings are best suited to place Ghostwalk's city of Manifest, and where would it be most problematic or require alot of adaptation work?

Ghostwalk is advertised as a sourcebook, and like Sturm said, page 134 gives advice for "Using Ghostwalk in Other D&D Worlds" (which really only explains how to use it with Forgotten Realms or Greyhawk).

I think the problem with those few paragraphs of advice is that you need to reboot the Ghostwalk gods, and make a zone of influence in Forgotten Realms, Greyhawk or another world, where the local cosmology is subverted (in order to introduce the thing where the souls of people do not vanish when they die).

Of course, once you start doing the sort of thing that Ripvanwormer was talking about with the Lendore Island, you make certain plot hooks in the Ghostwalk sourcebook problematic (because they conflict with your attempts to make Ghostwalk fit into the host setting). I think it can work, but that you would need to build yourself a homebrew guide for the specific campaign setting you want to merge Ghostwalk into. You would eventually end up with something that uses Ghostwalk, but which has to exclude (decanonise) certain parts of Ghostwalk (and maybe certain parts of the host setting) in order to make the two concepts work together.

TBeholder had a good alternative idea, when he suggested that you could use ideas peacemeal. That would certainly work. But I would personally find that less satisfying that being able to pick up Ghostwalk, along with a fan-made "Ghostwalk Conversion to Greyhawk" (or whatever) PDF and be able to run through the adventures in the Ghostwalk book in a way that was fairly similar to what was intended.

I think the easiest way to use Ghostwalk is as a standalone planet, where there is no conflicting cosmology to compete with what is going in in Manifest and where there is no conflicting pantheon that means that the Ghostwalk gods need to be tossed out.

But, in the interest of answering your discussion (instead of just saying: "Do not do this" and wagging the "badwrongfun finger of disaproval" ) I would suggest that the best way to use Ghostwalk with another campaign setting would be to build a Spelljammer crystal sphere around a planet that has Manifest and the surrounding lands on it.

A Ghostwalk crystal sphere ("Manifestspace" perhaps ) could use the lands from the Ghostwalk sourcebook, as a groundling area, but extend the themes out to the crystal sphere wall.

PCs (and NPCs) killed within the crystal sphere would simply convert into ghosts (Ghostwalk ghosts - not traditional D&D ghosts) instead of moving onto the afterlife. This would be a puzzle for the spacefarers to solve and landing on the planet and visiting the city of Manifest would be a cheap way to bring PCs or NPCs back to life.

With the same rules applying to the rivals of PCs, that could mean that the PCs kill a bunch of pirates that attack them, only for the same pirates to return months later, after getting their bodies back.

The main problem with a Manifestspace adaption of Ghostwalk to the Spelljammer universe is that anyone who dies and becomes a ghost does not have the power to manifest, unless they are within Manifest. So you end up with a bunch of dead PCs, NPCs and humanoid monsters that can't really do much (unless they can level up as a ghost - and they can't level up if they can't earn XP).

Having other places within the "Manifestspace" crystal sphere that cause ghosts to manifest could help with this. There are three gigantic balls outside of Manifest, that cause ghosts to manifest. So the thing that makes ghosts appear (and to be unable to become incorporal without special abilities to do that) is not limited to the city or the Gate of Souls.

Perhaps there could be one Manifest-like location on every celestial body (including any fireworlds ). Perhaps dead spacefarers would drift to the closest celestial body and then would manifest if they got to a Manifest-clone zone.

Perhaps smaller asteroids could be small enough to be totally contained within a Manifest-clone zone effect, meaning that there would be "Rock of Bral" like cities in space that were full of ghosts who wanted to hire spacefarers to go out and locate their bodies.

In a Manifest crystal sphere, it would be important to bring out the other themes of Ghostwalk.

The yuan-ti could be a major spacefaring faction, and could use snake-like spellamming ships. If they took over asteroids that were covered in Manifest-clone zones, but then hunted down and destroyed all the ghosts there, they could then execute individual spacefaring ghosts that drifted down to the surface of those asteroids. This could give you a scenario where the PCs need to sneak onto an asteroid, while polymorphed into yuan-ti, so that they could rescue a dead spacefarer who was hiding in ghost form and desperate to get off the asteroid and back into the void.

Of course, if you have (Ghostwalk) ghosts on asteroids in a (Ghostwalk) crystal sphere, they could probably just jump onto the gravity plane, swim outwards, and then drift off into wildspace.

The Cult of Orcus would be relatively easy to locate to a Spelljammer crystal sphere for Ghostwalk. They are already sailors. You could simply build a peaceful spelljamming port city (for example, one based on Dragon Rock in Realmspace) that gets taken over by cultists who murder everyone and raise them as undead. And there could be plenty of ships crewed by undead flying around "Manifest".

You could even have ghosts manifesting everywhere in wildspace, so that the entire crystal sphere became somewhere that dead PCs could explore. However, that might take away from the theme of the city of Manifest being "important".

Perhaps a way to get around this could be to create other places in Manifestspace where ghosts can manifest, but keep the Gate of Souls below the city of Manifest on the Ghostwalk planet and require PCs and NPCs to go there to get brought back to life.

If that was done then most of the important themes of Ghostwalk could spread out to fill an entire crystal sphere, but Ghostwalk itself, would lie at the heart of that sphere without being messed up too much.

And if you wanted to find a way to involve ghost PCs in Spelljammer action, then one of the easiest ways to do that would be to make spelljamming helms create a zone of manifestation while they were active.

This would mean that NPCs or even enemy NPCs who got killed in combat, would get up and carry on doing stuff...and might not initially realise they were dead (until they looked down and saw their body).

When their ship landed somewhere, they would loose their ability to manifest, so you would have ghosts who could work as ship's crew, but not do so much if they were not onboard a ship. That could have interesting implications for spacefaring commerce. You could also have ghost helmsmen*!

* = Ghost helmsmen would be doing the graveyard shift.

If you go with the one-manifest-zone-per-celestial-body logic, then it would actually be in the interest of ghost spacefarers to travel to small asteroids, where all or most of the surface would allow them to manifest. And to only visit spelljamming ports on larger celestial bodies that were known to have manifest zones at the ports.

Another approach to the "Ghostwalk expanded to crystal sphere" thing, would be to create some sort of random table for manifest zones, where some manifest zones were as strong as the city of Manifest, and other zones were weaker (or maybe even stronger). Suppose, for example, that a ghost could manifest in a weak manifest zone, but only if they were concentrating on being manifested. Ghosts might automatically go incorporeal, if they fell asleep.

Ioun stones, that cause ghosts to manifest, might also be useful, in an expanded setting.

Am gearing up to use Minaria (from TSR's Divine Right boardgame; see also many articles in early issues of The Dragon) as a campaign world and decided to use Ghostwalk modified to be the *backstory* for the city of Khos.

"For more than thirty-four centuries the city of Khos has stood deserted by man, shunned by the tribesmen and nations of eastern Minaria. According to the travelers who have visited it, majesty still clings to the ruins of Khos -- but also mystery and danger." Minarian Legends

Take Manifest and let millenia pass, imagine the city in ruin, and pull out the best of the play mechanics for a D&D based campaign.